Does anyone have any ideas. I've had this problem for some time. Listening to voice messages delivered from the outside are terrible. Sometimes you can hardly hear the caller. I am running the PRI as MGCP to Call Manager with echo cancellation enabled and echo suppression. I have the latest IOS code installed. Problem does not occur internally. I even upgraded Unity to 4.0.3 with no success. There is absolutely no problem with regular phone conversations.